Underreamer.



E. L. MILLS.

UNDERREAMER.

APPLlcATmN msn Dsc. 4. 1916.

Patented Apln LQQLBB.,

2 SHEETS-SH Wulff/ll.

E. L. MILLS'.

UNDERREAMER.

-SHEE 2.

EDWABD'L. WELLS, OFTLOSANGELES, 'CALIFRNI`;A.

l U-NDERREAMER.

Application filed December 4,1916.

To all whommay concern.'

'Be yit known vthat l, EDWARD L. MiLLs, a citizen of theiUnited States, residing at Los Angeles,'in the county of Los Angeles, State of California, have invented new and useful 'Improvements in Underreamers, of which the .following is a specification.

This invention relates to'improvementsin underreamers; and particularly to improvements in my underreamer shown and described inmy application .onunderreamera Serial 'Numberl117f/i60, filed August 29th, 1916. v

Said application contains the broader claims to 'the general combinations therein set forth; while'this applicationhasparticularly to do with improvements in the shape of the cutters and the mandrel tongue'sun rounded by the cutters and withthe means for supporting the cutters.

l explain a preferred form ofunderreamer embodying my invention `in `the following specification, reference'being hadto the accompanying drawings, inwhich, for` the purposeof this specification, 'l illustrate said preferred embodiment. Inthese drawings Figure 1 is a side elevation of my underreamer in its expanded or operative posi tiong'Fig. r2 is a side elevation of the lower parts thereof, contracted within .a well casing; Fig. '3 is a'longitudinal section taken `as indicated by line 3 3 on Fig. 1; Fig. .4; is a bottom view of'the underreamer in its eX- pand'ed position; Fig. 5 is a side `elevation of the 'lower part of the mandrel and the tongue;'Fig. G'is a bottom'view ofthe mandrel and tongue; Fig. 7 is another side view of the lower part of the mandrel and tongue; Fig. 8 is a section taken as indicated by line 8 8 on Fig. 3, showing a vertical section of the cutters and showing their elevating means; Fig. 9 is an enlarged cross section taken as indicated by line 9 9 on Fig. 3; Fig. 10 is a section taken as indicated byline 10-10 on Fig. 9; Fig.11 is an enlarged cross section taken as indicatedbyline 11 11 on 3; Figs. i12 and '18 are enlarged cross sections taken as indicated, respectively,'by lines 12 12 and 18 13 on Figs. 3 and 8; Fig1`4 is aside view of the parts shown in Figs -and10; LFig. 1.5 is a similar view showing a modification; and Fig. 16 is a perspective of a cutter.

in the drawings 'the numeral 10 desig nates a mandrel which, according to my invention, Amay be and preferablyis, in one Specification of Letters Patent.

llatented Apr. 3, i917.

Serial No. 134,787.

piece. The manner in which the cutter elevating and supportingboltsaremounted in and inserted in the mandrel makes itpossibletouse a onespiece mandrel; thus making the mandrel of vthe maximum strength.

-This mandrel isprovided at its upper end with any usual arrangement 10afor 4connectionto a string of drillingtools; and at its lower end it hasra downwardly extending tongue 11. This tongue 11 is'preferably of the configuration shown in the various views, having opposite, vertical, parallel bearing faces 12.. These bearing .faces 12 face outwardlyfandxare.two innumber, (the number of cutters? in this f preferred construction' being two. lt will be understood, however, thatthelnuniber ofcutters'may be two-or more, asdesire'd.) .At each of the opposite edges of'tlie'bearing faces lQthevv tongue 11 has overhanging edgeportions 13whose"inner faces form inwardly facing bearingfaces 1i which face inwardlytowardeach other. These overhangingportions 13 and bearing facesfld. extend down'the sides of theitongue and continuously-across its curved lower Aend, as illustrated and .as more fully-notedhereinafter. rlhelower end ofthe tonguehas a downward extension lwith lower vdiagonal surfaces 16; and at the upper end ofthe-extension, at the lower end ofthe main part lof the tongue, there are downwardly lfacing shoulder surfaces 17 and 81. Atthedower end of the mandrel'lO, and at theupper endof'theltongue 11,V there is a downwardlyffac ing shoulder 18; and, as hereinafter eX- plained, the cutters when in their operative or expanded 4.position bear upwardly against the shoulders 17, 81 and 18. The lower ends of thetongue, and of the tongue extension 15, are rounded, as shown in Figs. 'and 7. The overhanging `ledges 13 are carried around the bottom ofthe tongue, making a formation with recessedsurfaces 81 at'the tongue bottom. rThe lower diagonal surfaces 16 are 'also rounded; and, as hereinafter eX- plained, the cutter recesses lare correspondingly shaped.

Vithin the mandrell() l makemplurality ofbores 20, their number depending upon the number of cutters, which in this case is two. Accordinglythere are two'of'these bores 2O situated opposite each other,finthe position shown relativeto the tongue 11. lt will be noted thatthe'boresare entirely exterior ofthe tongue; that is, that theyl are outside of the side surfaces or planes ofthe tongue,^as is clearly shown in Figs. 3 and 6. The cutter supporting bolts 21 extend up into the bores. Bolts-21 are supported by compression springs-22, the upper ends of these springs pressing upwardly upon nuts 23 on the upper ends of the bolts and the lower ends of the springs resting upon sleeves 24 which surround the bolts Vand fit into the bores 20. The means for raising and supporting sleeves 24 is one of the improvements herein particularly concerned. I provide each sleeve 24 with a lug or other projection 25, and the mandrel bores 20 have vertical side slots 26 through which the lugs 25 may be passed upwardly to emerge into side openings 27. These openings 27 are of the general configuration shown, open to the exterior cylindrical face of the mandrel, and are of such extent as to allow the lugs 25 to be turned (by rotating' the lugs and sleeves) from positions over the slots 26 to the positions shown in Figs. 9 and 14.

The bottom wall of each opening 27 is preferably shaped as shown in Fig. 14; having a rising incline 28 Vup and over which the -lug 'may be forced, and then a short dropping incline 29 over which the lug is moved to reach its final position resting on the surface 80. This surface 30 is elevated with reference to the surface 30a which marks the upper termination of the slot 26 and from which surface 30"L the incline 28 rises. W'hen the bolts, sleeves, etc., are initially placedin the bores 20, the lower ends of the sleeves rest on enlargements 31 on the lower `ends of the bolts, andthe lugs 25 pass through slots 26, and are just clear of the slots and in the openings 27 when the upper ends of the cutters engage the lower end of the mandrel. The rotational movement of the lugs 25 is effected in any suitable manner and with any suitable tool, as by placing a tool behind them and driving them over from one position to the other. l/Vhen the lugs are in the positions illustrated, then the sleeves 24 are raised off the enlargements 31 a slight distance. This distance need be no more than necessary to give `a working clearance between the sleeves 24 and enlargements 31 ,and to provide for Yany slight wear of the parts.

In Fig. l5 I show a modification wherein the surfaces 30 and 30FL are separated by a square surfaced projection 28a. In this form the lug 25, instead of being driven over inclined surfaces, must be lifted up and then moved over from one position to the other. The lifting of the lug may be accomplished by driving a tool under it. It

will be seen that, in essentials, the two forms of device are substantially the same.

When in their final positions the sleeves then form stationary supports for the lower ends of compression springs 22; and the springs then tend to lift the bolts 21 upwardly. The upward movement of the bolts is limited by the upward movement of the cutters to which the lower ends of the bolts are connected.

Each bolt has upon its lower end a rectangular head 35, each of which heads eugages in notches 36 in the upper ends of the cutters 87. The cutters 37 surround the tongue l1, each of the cutters being recessed on the inner face, as illustrated, and as will hereinafter be described in detail. At their upper ends the cutters completely surround the tongue 11, as is shown in Figs. l, 2 and 11. The points at which the cutters meet .are directly beneath the bolts 21 and the rectangular heads 35 each engage half in one cutter and half in the other. Each cutter is provided with two notches 3G; and the edgeof the bolt head 35 enters under the overhanging upper wall 36a of these notches. The bolt heads fit freely in the notches so that the cutters may have the relative motions hereinafter described, without binding upon the bolt heads; and yet the bolt heads it the notches with sui'iicient accuracy so that when one cutter moves vertically the other Jcutter will be caused to correspondingly move, through the medium of the bolt heads 35. This freedom of movement, with accuracy of connection, is facilitated by slightly sloping` the lower surfaces of the notches 36, as shown at 3Gb in Fig. 8. It will be noted, particularly by reference to Fig. 8, that the points where the two opposite cutters connect with the bolt heads 35 are very close together; so that the bolt heads form short and rigid connections bctween the two opposite cutters. This obviates the possibility of .any binding or twisting of the bolt head when one of the cutters is moved vertically.

Each of the cutters has a lower cutting or drilling end 40 and an exterior surface 41 adapted to engage the inner surface of the casing as is shown in Fig. 2. The side surfaces of each cutter are preferably fiat, as shown at 42; excepting that at the top of each cutter there is a portion whose exterior surface is practicallyv semi-cylindrical, as is illustrated at 43. It is at this point, at the upper ends of the cutters, that the cutters completely surround the tongue 11 and meet each other, or substantially meet each other, at their surfaces 44. Then the cutters are in their expanded position, thesev surfaces bear against each other; and when the cutters `are in their contracted position, as shown in 2, the surfaces 45, directly below the surfaces 44, are bearing against each other. The line at 45a (see Fig. 1(3) at the upper edges of surfaces 45, may be taken to represent the axis about which the cutters swing when expanding and contracting. This may be readily seen by inspection of Figs. 2 and 8. Below the point represented by the line 45a the cutters are of such contiguration as to leave a space between themfor the purpose of allowing their contraction. rlhe cutters have inwardly facing opposite surfaces 47 which bear against each other when the cutters are contracted; and above these surfaces 47 there is a space adapted to acconunodate a stop-pin 48. The downward movement of the cutters is limited by shoulders 49 moving down onto this stop pin, set through the tongue 11.

Each of the cutters is recessed on'its inner face, the recess being open at the upper and inner faces. This is clearly shown in Fig. 16. The back wall of therecess has an uppermost vertical surface 50 which bears against the surface 12 of the tongue 11 when the cutters are in their expanded position; then an intermediate, downwardly and outwardly receding surface 51 which bears against the surface 12 of the tongue when the cutters are collapsed, as shown in Fig. 2, and the curved diagonal surface 52 below the surface 51 being then belowfthe lower shoulder 17 of the tongue; and .at its bottom this back wall of the recess has another vertical surface in the same plane as surface 50, which vertical surface 53 bears against the lower' part of the surface 12 when the cutters are expanded.

The bottom of the recess is formed by the curved bottom surface 54 which bears upwardly against the lower curved shoulder 17 of the tongue when the cutters are expanded and which lies below the lower curved diagonal surfaces 16 of the lower extension of the tongue when the cutters are contracted. The recess has an overhanging front wall at each of its opposite sides, which overhanging front walls present a pair of inwardly facing surfaces 55, vertical and parallel to the back surfaces 50 anc 53 of the recess. These surfaces 55 hear against the inwardly facing surfaces 14 of the tongue when the cutters are expanded. The surfaces 55 eX- tend upwardly to points opposite the lower edge of the upper back vertical surface 50, and from that point upwardly they rec-ede from vertical surface 50, as is illustrated at 56. When the cutters are in their conipressed position, the surfaces 56 bear against the inward surfaces 14 of the tongue, as indicated in Fig. 2. The overhanging front walls of the recess, and the inner surfaces 55, are continued on in a curve to form the upwardly projecting curved ledge 80 in front of the bottom 54 of the recess. This ledge 8O lits up behind the curved surface 17 on the tongue, bearing up against the curved recessed surface S1 on the tongue; and this interengagement of the ledges on the tongue and cutter makes the structure particularly strong against spreading of the cutters. These parts 80 and 17 are seen to be continuations of the side parts described, continuing these-parts across the bottoms of the tongue and recess. The lower surfaces 16 on the tongue being rounded, they lit the shape of the curved ledges S0 and do not mutilate them when the cutters move up from the position shown in Fig. 2; This is also true of the curved surfaces 17 and the diagonal curved surfaces 52.

Below the surface 54 at the bottom of the recess there is a vertical inwardly facing surface 60 on each cutter which bears against the vertical face 61 of the extension 15 of the tongue when the cutters are expanded. These surfaces 60, together with the lower vertical surfaces 53, constitute double spreading surfaces and support the lower ends of the cnttersagainst movement toward each other,` and against the stress or force which tends to crush them toi Yard each other. The bearing of the surfaces 55 (which surfaces may be termed rentrant surfaces) upon the inward surfaces 14 of the tongue, supports the cutters against outward movement, Tt will be noted that the surfaces 55 and 14 bear upon each other for a considerable vertical distance; and across the bottom of the tongue and of the recess; and it will be noted that the cutters have opposite bearing surfaces 50 and 53 spaced at the top and bottom of the recess, so that each cutter is firmly held in position both against the stresses which tend to move it outwardly and stresses which tend to mov-e it inwardly.

Provision for holding the cutters -firmly against lateral motion is made by the hearof the side surfaces 65 of the recess` against the side surfaces 66 of the tongue, and the bearing of surfaces 67, of the front walls of the recess, against side surfaces 68 of the tongue. Furthermore, it will be noted that at the sides of the vertical surface 16 there are small lateral surfaces 69 which bear against the side surfaces 70 of the lower eX- tension 15 of the tongue. These lateral surfaces 69 are not very large in extent; but

they are situated low on the cutter, at a point close to the cutting end, and therefore materially aid in strongly supporting'the lower ends of the cutter against lateral displacement.

It will be noted that the exterior corner edges of the projecting parts 13 of tongue 11 are rounded away, as indicated at 13a; and that the back corner lines of the cutter recess are correspondingly rounded, as indicated at 87a. This construction not only makes the recess easier to manufacture-the rounded corners being more easily formed than square oneswbut it also materially strengthens the cutters by making them thicker at the points indicated by the numeral 37b in Fig. 12.

As I have hereinbefore stated, it is one of the features of my reamer that the tongue is solid, and not weakened by bores, slots, or

par

any of the usual openings therethrough. I obviate the weakening of the tongue by putting the cutter elevating means exterior of it; and by putting the cutter elevating means in this position I make it possible to insert said means in the mandrel from below. The means for raising and holding the cutter elevating means is one of the particular subjects of this application. Making the cutters external-making them surround the tongue-facilitates connection to the elevating means situated laterally; and facilitates short interconnection between the cutters. And making the critters Aexternal also has many other advantageous features as herein stated. And the improved shape of the cutters is another subject of thisvapplication.

I have described a preferred embodiment of my invention; but I do not consider my invention to be limited to the specific structure and detailsl herein explained.` Within the scope of the appended claims various 'changes in form and arrangement may be made without departing from my invention.

. Having described a preferred'form of my invention, I claim:

1. In an underreamer, the combination of a mandrel with a downwardly projecting cutter carrying tongue, recessed cutters surrounding the tongue and vertically movable thereon, the lower end of the tongue being rounded and the bottoms of the recesses being rounded and facing upwardly and bearing upwardly against the lower rounded Vend of the tongue, and means to normally hold the cutters up on the tongue.

v2. In an underreamen/the combination of a mandrel with a downwardly projecting cutter carrying tongue, recessed cutters surrounding the tongue and vertically movable thereon, the lower end of the tongue beiuf:- rounded and the bottoms of the recesses be ing rounded and bearing upwardly against the lower rounded end of the tongue, a downward extension on the tongue having .diagonal curved surfaces at its lower end adapted to engage the front edges of the curved bottoms of the cutter recesses when the cutters are lowered on the tongue, and the back walls of the cutter recesses having diagonal curved surfaces adapted to be drawn over the curved lower ends of the tongue when the cutters are moved upwardly, and means to normally hold the cuttersup on the tongue.

. 3. In an underreamer, the combination of a mandrel having a downwardly projecting tongue with opposite outwardly facing bearing faces and with opposite inwardly facing bearing faces formed by the inner surfaces of overhanging edge portions of the tongue, cutters vertically movable on the tongue substantially entirely surrounding the same and having spreading surfaces adapted to bear against the outward faces of the tongue and having rentrant 0utwardly facing surfaces bearing against the inward faces of the tongue, and means to normally hold the cutters in their upper positions on the tongue, the lower end of the tongue being curved and the cutters having upwardly facing correspondingly curved surfaces to bear upwardly against the lower curved end of the tongue.

4. In an underreamer, the combination of a mandrel having a downwardly projecting tongue with opposite outwardly facing bearing faces and with opposite inwardly facing bearing faces formed by the inner surfaces of overhanging edge portions of the tongue, cutters vertically movable on the tongue substantially entirely surrounding the same and having spreading surfaces adapted to bear against the outward faces of the tongue and having rentrant outwardly facing surfaces bearing against the inwardly facing bearing faces of the tongue, and means to hold the cutters in their upper positions on the tongue, said inwardly facing bearing faces of the tongue extending in curved formation across the lower end of the tongue, and said rentrant bearing faces of the cutters extending in similar curved for mation across the lower parts of the inner faces of the cutters.

5. In an underreamer, the combination of a cutter carrying tongue having vertical outward bearing surfaces and having inward bearing surfaces extending vertically along the sides of the tongue and across its bottom, and recessed cutters fitting around the tongue having surfaces at the back of the recesses bearing against the outward faces of the tongue and having rentrant surfaces formed on overhanging front walls 1 at the sides and bottoms of the recesses, said rentrant surfaces adapted to bear against the inward bearing faces of the tongue, the bottom of the tongue and the bottoms of the recesses being curved from side to side.

6. In an underreamer, the combination of a cutter carrying tongue having outward bearing faces, the lower end of the tongue being curved from side to side, overhang ing edge portions extending along the edges of the outward bearing faces and extending in curves across the bottom of the tongue from side to side; and recessed cutters adapted to fit around the tongue, the bottoms of the recesses being curved from side. to side, and the recesses having frontavalls on their sides and curved across their bottoms forming continuous rentrant surfaces facing the backs of the recesses and extending continuously along the sides of the recesses and curved across its bottom.

7. In an underreamer, a cutter elongated in form with a lower cutting end, having a recess open on the inner and upper faces of the cutter, the back wall of the recess having a downward and outwardly receding surface, a forward and downwardly inclined surface curved from side to side of the recess, and a lower vertical surface, the said recess having re-entrant front walls with surfaces facing the back wall, and having a bottom surface curved from side to side.

8. In an underreamer, a cutter elongated in form with a lower cutting end, having a recess open on the inner and upper faces of the cutter, the back wall of the recess having a downward and outwardly receding surface, a forward and downwardly inclined surface curved from side to side ofthe recess, and a lower vertical surface, the said recess having rentrant front walls with surfaces facing the back wall, said rentrant front walls extending along both opposite vertical sides of the recess and across its bottom in curved formation, and the bottom of the recess being curved from side to' side.

9. In an underreamer, the combination of a mandrel having a vertical bore, a vertically movable cutter, a bolt connected at its lower end with the cutter and extending up into the mandrel bore, a spring surrounding the bolt, a supporting sleeve for the lower end of the spring fitting around the bolt and into the bore, a side lug on the sleeve, the mandrel having a slot as a side extension of the bore, and having a side opening at the upper end of the slot opening out to the outer face of the mandrel, said side opening having an inclined bottom surface.

10. In an underreamer, the combination of a mandrel having a vertical bore, a vertically movable cutter, a bolt connected at is lower end with the cutter and extending up into the mandrel bore, a spring surrounding the bolt, a supporting sleeve for the lower end of the spring fitting around the bolt and into the bore, a lug on the spring supporting sleeve, and an inclined surface on the mandrel. over which the lug is moved to lift the sleeve.

11. In an underreamer, the combination of a mandrelihaving a vertical bore, a vertically movable cutter, a bolt connected at its lower end with the cutter and extending up into the mandrel bore, a spring surround ing the bolt, a supporting sleeve for the lower end of the spring fitting around the bolt and into the bore, a lug on the spring supporting sleeve, the mandrel having an opening into which the lug projects and the bottom surface of the opening having a supporting` surface for the lug.

12. In an underreamer, the combination of a mandrel, a plurality of cutters vertically movable thereon, spring bolts connected to the cutters and extending up into the mandrel, springs around the bolts, and means for independently raising and supporting each of the springs in the mandrel, each of said means embodying a wedge means.

13. In an underreainer, the combination of a mandrel, a plurality of cutters vertically movable thereon, spring bolts connected to the cutters and extending up into the mandrel, springs around the bolts, and means for independently supporting each of the springs in the mandrel, embodying a sleeve surrounding each bolt beneath the spring, a lug on each sleeve, and the mandrel having lugs supporting surfaces over which the lugs may be turned by rotating the sleeves.

lei. In an underreamer, the combination of a mandrel with vertical bores therein near its surface, a plurality of cutters vertically movable on the mandrel, bolts connected to the cutters and extending up into the bores, springs around the bolts, and means for independently supporting each of the springs in the mandrel, embodying a sleeve surrounding each bolt beneath the spring thereon and situated in the mandrel bore, a side lug on the sleeve, the mandrel having vertical slots as side extensiens of the hores through which slots the side lugs may be passed upwardly, and the mandrel having side openings extending out from the bores to the mandrel surface at the upper ends of the side slots, and the bottom of each of said side openings having a supporting surface for the lug with an inclined raising surface leading up to it.

i 15.V In an underreamer, the combination of a mandrel, a plurality of cutters vertically movable thereon, spring bolts connected to the cutters and extending up into the mandrel, sarings around the bolts, and means for independently raising and supporting each of the springs in the mandrel, each of said raising and supporting means embodying a rotatable spring supporting sleeve surrounding the bolt, and wedge means on the mandrel adapted to be engaged by the sleeve whereby rotation of the sleeve causes the sleeve to rise.

16. In an underreamer, the combination of a mandrel with a vertical bore, a cutter vertically movable on the mandrel, a bolt connected at its lower end to the cutter and eX- tending up into the mandrel bore, a spring supporting the belt, and means to raise and support said spring embodying a rotative sleeve around the bolt, and wedge means on the mandrel adapted to be engaged by the rotative sleeve whereby rotation of the sleeve causes the sleeve to rise.

17 In an underreamer, the combination of a mandrel with a vertical bore, cutter vertically movable on the mandrel, a bolt connected at its lower end to the cutter and extending up into the mandrel bore, said bolt having an enlargement near its lower end, a spring supporting the bolt, and means to raise and support said spring embodying a rotative sleeve around the bolt, said sleeve normally resting on Said bolt enlargement, and Wedge means on the mandrel adapted to be engaged by the rotative sleeve whereby rotation of the sleeve causes the sleeve to rise oit the bolt enlargement.

18. In an underreamer, the combination of a mandrel with a vertical bore and with a side opening leading out from the bore above the lower end of the mandrel, the lower vvall of Said side opening having an inclined plane, a cutter vertically movable on the mandrel, a bolt connected at its lower end to the cutter, a spring supporting the bolt, and a rotatable spring supporting sleeve around the bolt having a lug adapted to project into said side opening over the inclined plane.

19. In an underreamer, the combination of a mandrel With a vertical bore, with a side opening leading out from the bore above the lower end of the mandrel, and with a side slot for said bore extending from the lower end of the mandrel up to said side opening, a cutter vertically movable on the mandrel, a bolt connected at its lower end to the cutter, a spring supporting the bolt, and a rotatable spring supporting sleeve around the bolt adapted to be passed up through the bore to a point opposite the side opening, said sleeve having a side lug adapted to be passed up through said side slot and to project into said side opening,

said side opening having an inclined plane on its bottom and said lu adapted to be moved over said inclined pIane by rotation of the sleeve and lug.

20. In an underreamer, the combination of a mandrel with a vertical bore, with a side opening leading out from the bore above the lower end of the mandrel, and with a Side slot for said bore extending from the lower end of the mandrel up to said side opening, a cutter vertically movable on the mandrel, a bolt connected at its lower end to the cutter and having an enlargement near its l lower end, a spring supporting the bolt, and a rotatable spring supporting sleeve around the bolt resting up through the bore to a point opposite the side opening, said sleeve having a side lug adapted to be passed up through said side slot and toproject into said side opening, said side opening having an inclined plane on its bottom and said lug adapted to be moved over said inclined plane byV rotation of the sleeve and lug thereby to raise the sleeve oft1 the bolt enlargement.

In Witness that I claim the foregoing I have hereunto subscribed my name this 27th day of November 1916.

EDVARD L. MILLS.

Witnesses:

JAMES T. BARKELEW, ELWooD H. BARKELEW.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

